In large-area backlighting applications such as in light advertising, advertising panels are used, for example, which are equipped with photographic images and backlighting devices for illuminating the photographic images. If the backlighting is effected by LEDs, then junction temperatures of different magnitudes can arise for the different LEDs. The advertising panels are typically situated in an upright position. As a result, the LEDs in the lower region of the advertising panel can emit their heat upward. This has the consequence that the LEDs in the middle and upper regions of the advertising panel are exposed to a higher temperature than the LEDs in the lower region, which leads to higher junction temperatures of these LEDs. However, different junction temperatures of the LEDs give rise to different brightnesses in the application and cause a color locus shift. In long-term application this can additionally lead to different aging behavior of the LEDs, which is in turn manifested in a color locus shift and a change in brightness.